Patterned Ionic Resistance for Uniform Die-Level Electroplating
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Solution Overview
Problem
In semiconductor device manufacturing, electroplating processes often result in non-uniform metal deposition due to variations in ionic current distribution, leading to excessive plating in isolated features and insufficient plating in dense features, which affects the uniformity and reliability of metal layers in substrates with complex feature patterns.
Innovation Solution
The use of a tailored ionically resistive ionically permeable element or a grid-like shield with varying local resistance patterns is introduced, positioned close to the substrate to align with the substrate's feature patterns, allowing for controlled ionic current distribution and uniform metal deposition by matching high resistance areas with isolated features and low resistance areas with dense features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional electroplating is used without resistance control, then plating process is simple, but plating uniformity deteriorates due to excessive plating in isolated features and insufficient plating in dense features
Solution Approach 1:
The patent applies local quality by creating regions of different ionic resistance within the electroplating apparatus. Specifically, it uses ionically resistive elements with spatially varying resistance patterns, or selectively positioned shields, to create high resistance regions aligned with isolated features and low resistance regions aligned with dense features. This local differentiation of resistance properties enables precise control over ionic current distribution, ensuring uniform plating across features with varying densities without requiring complete redesign of the entire apparatus.
Solution Approach 2:
The patent introduces ionically resistive elements or shields as intermediary components between the electrolyte and the substrate. These intermediaries selectively modulate the ionic current reaching different regions of the substrate - the resistive elements act as mediators that reduce excessive current to isolated features while allowing sufficient current to dense features. This intermediary approach achieves plating uniformity by inserting a controllable resistance layer into the electroplating system rather than directly modifying the substrate or electrolyte composition.
2Manufacturing precision
If uniform ionic current distribution is achieved, then plating uniformity improves, but current distribution control becomes more difficult
Solution Approach 1:
The patent applies parameter changes by systematically varying the ionic resistance parameter in specific spatial regions. It uses ionically resistive elements with engineered resistance patterns, or selectively positioned conductive shields, to change the resistance parameter locally - creating high resistance in regions corresponding to isolated features and low resistance in regions corresponding to dense features. This parameter modification approach simplifies operation by providing a straightforward mechanism (resistance variation) to achieve uniform current distribution and plating uniformity without complex control systems.
3Manufacturing precision
If ionically resistive element with varied local resistance is used, then excessive plating in isolated regions is reduced, but element design complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the ionically resistive element into distinct regions with different resistance characteristics. Each region is designed to correspond to specific feature patterns on the substrate - with high resistance segments aligned to isolated features and low resistance segments aligned to dense features. This segmentation of the resistive element into functionally differentiated zones enables precise control over current distribution to various substrate regions while maintaining a relatively simple overall element structure that can be manufactured using standard techniques.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly improves plating uniformity by reducing excessive plating in isolated regions and ensuring sufficient plating in dense regions, achieving high fidelity tailored source current distribution and desired metallization height uniformity across the substrate.
Implementation Method 1
the element allows for flow of ionic current through the element towards the substrate during electroplating
Implementation Method 2
a plating chamber configured to contain an electrolyte and an anode while electroplating metal onto a semiconductor substrate
Data Source
AI summary
An apparatus for electroplating a metal on a semiconductor substrate with high control over plated thickness on a die-level includes an ionically resistive ionically permeable element (e.g., a plate with channels), where the element allows for flow of ionic current through the element towards the substrate during electroplating, where the element includes a plurality of regions, each region having a pattern of varied local resistance, and where the pattern of varied local resistance repeats in at least two regions. An electroplating method includes providing a semiconductor substrate to an electroplating apparatus having an ionically resistive ionically permeable element or a grid-like shield having a pattern correlating with a pattern of features on the substrate, and plating metal, while the pattern on the substrate remains spatially aligned with the pattern of the element or the grid-like shield for at least a portion of the total electroplating time.